A traditional casting process for forming metal castings employs one of various types of molds for example, a green sand mold, a precision sand mold, or a steel die, having the exterior features of a desired casting, such as a cylinder head or engine block, formed on its interior surfaces. A sand core comprised of sand and a suitable binder material and defining the interior features of the casting is placed within the mold or die. Sand cores generally are used to produce contours and interior features within the metal castings, and the removal and reclaiming of the sand materials of the cores from the castings after the casting process is completed is a necessity. Depending upon the application, the binder for the sand core and/or sand mold, if used, may comprise a phenolic resin binder, a phenolic urethane “cold box” binder, or other suitable organic binder material. The mold or die is then filled with a molten metallic alloy. When the alloy has solidified, the casting generally is removed from the mold or die and may be then moved to a treatment furnace(s) for heat-treating, reclamation of the sand from the sand cores, and, at times, aging. Heat treating and aging are processes that condition metallic alloys so that they will be provided with different physical properties suited for different applications.
In accordance with some of the prior art, once the casting is formed, several distinctly different steps generally must be carried out in order to heat treat the metal casting and reclaim sufficiently pure sand from the sand core. A first step separates portions of sand core from the casting. The sand core is typically separated from the casting by one or a combination of means. For example, sand may be chiseled away from the casting or the casting may be physically shaken or vibrated to break-up the sand core and remove the sand. Once the sand is removed from the casting, heat treating and aging of the casting generally are carried out in subsequent steps. The casting is typically heat treated if it is desirable to, among other treatments, strengthen or harden the casting or to relieve internal stresses in the casting. An additional step consists of purifying the sand that was separated from the casting, including burning the binder that coats the sand, abrading the sand, and passing portions of the sand through screens. Therefore, portions of sand may be re-subjected to reclaiming processes until sufficiently pure sand is reclaimed.
There is, therefore, a desire in the industry to enhance the process of heat treating castings and reclaiming sand core materials therefrom such that a continuing need exists for a more efficient method, and associated apparatus, that allow for more efficient heat treatment, sand core removal, and reclamation of sufficiently pure sand from the sand core.